The present invention relates to a pilot-operated proportional pressure limiting valve. The invention also relates to a method of operating a pressure limiting valve.
Pilot-operated proportional pressure limiting valves are known. One known proportional pressure limiting valve is described in the book "Der Hydraulik Trainer", Vol. 2, published by Mannesmann Rexroth GmbH, Lohr/Main, pages B20 and B21.
From DE 38 24 089 A1 a pilot-operated proportional pressure limiting valve having a control oil nozzle arranged in a main piston is known. In order to obtain a very small adjustable pressure, the outlet of a control oil nozzle for the feeding of control oil to a pilot-operated valve is brought directly out of the main piston by connecting means.
The proportional pressure limiting valve in accordance with DE 38 24 089 A1 tends under certain circumstances to vibrate in the region of small volumetric flows and high pressure. Therefore, a damping nozzle is already provided in the main piston in the valve according to DE 38 24 089 A1. Since, however, within the above-indicated range, the control stroke of the main piston is very small and thus the volume of control oil displaced via the damping nozzle from the control space is also very small, the damping action of the damping nozzle on the control stroke of the main piston is too weak and the valve cannot be prevented from vibrating within this region.